Call Options
A contract giving the buyer the right — not the obligation — to BUY 100 shares of the underlying at the strike price before expiration; the buyer is bullish, and the seller (writer) is obligated to deliver if exercised.
Calls offer leveraged upside: a small premium controls 100 shares. Writers take the opposite view and keep the premium if the option expires worthless — but a naked call writer faces unlimited risk, the most dangerous position on the exam.